Transmission and receiving system



Oct; 28-, 19240 1,513,707

J. H. HAMMOND,- JR

TRANSMISSION AND RECEIVING SYSTEM Original il Aug. 1919 2 Sheets-Sheet 15 9% "Huh",

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- J. H'-., HAMMOND, JR

TRANSMISSION AND RECEIVING SYSTEM Original Filed Aug. 5, 1919 2Sheets-Sheet 2 Patented Oct. 28, 1924.

JOHN HAYS HAMMOND, JR-., F GLOUCESTER, MASSACHUSETTS TRANSMISSION ANDRECEIVING SYSTEM,

Original appllication filed August 5, 1919, Serial No. 315,463. RenewedJanuary 25, 1923. Patent No.

1,472,218, dated October 30, 1923. 652,900. v i

To all 10720712 it may concern: I

Be it known that 1, JOHN Hays HAM- eiono, J12, a citizen of the UnitedStates, and a resident of Gloucester, in the county of Essex and Stateof Massachusetts, have invented certain new and useful Improvements inTransmission and Receiving Systems, of which the following is aspecification, this application being a division of my application, Ser.No. 315,463, filed Aug. 5, 1919, and renewed Jan. 25, 1923.

Some of the objects of the present invention are to provide a method andapparatus for transmitting and receiving messages; to provide means forimpressing upon a series of emitted waves a plurality of series ofperiodic variations or modifications of different frequenciesrespectively and impressing on said waves and variations a series ofirregular modifications corresponding to a message; to provide means forselecting from a series of received waves a predetermined series ofperiodic variations; to provide means for transmitting and receiving 25telephonic and telegraphic messages through the medium of irregularmodifications impressed upon a plurality of series of periodicvariations of different frequencies respectively; and to provide otherimprovements as will hereinafter appear.

In the accompanying drawings, Fig. 1 represents diagrammatically -oneform of transmitting apparatus embodying the present invention; Fig. 2represents diagrammatically one form of receiving apparatus embodyingthe present invention; and Fig. 3 represents a fragmentary portion ofthe receiving apparatus employed when the sys- 'tem of the invention isused'in connection with telephony.

Referring to the drawings, the transmitting apparatus shown in Fig. 1comprises an open, aerial circuit 10, having a second ary inductance 11grounded at 12, the said circuit constituting the medium fortransmitting radiant energy waves into space to be received by anapparatus to be hereinafter described.

For causing the aerial circuit 10 to emit frequency, the secondary coil11 of the aerial circuit 10 is inductively coupled to a primary coil 13located in a closed circuit ll y eutcdyne or thermioni waves of radiantenergy of a suitable high oscillator 15. The circuit Divided and thisapplication filed July 21, 1923'. Serial No.,

14 includes a batand for starting uction, as shown,

consists of an evacuated bulb'20 having enclosed therein a plateterminal 21 a grid 22 a rheostat 25. The oscilla and a filament 23arranged to be heated by a battery 24 and tor 15 is arranged to becontrolled by a closed circuit. 26 includ ng two secondary coils 27 and28 and a variable condenser 29, the function of said circuit '26 beingtoreact u nder the influence of the tickling coil 17 when the key 18 isclosed. This reaction causes tube 15 to oscillate and acting throughcoils 13 and 11 causes the aerial circuit 10 in a well known manner toemitradiant waves of a high fresecond.

quenc'y,'for example, 1,000,000 cyele per In order to impress upon thehigh frequency waves emitted by the aerial circuit 10 periodicvariations in amplitude the secondary coils 27 and 28 are inductivelycoupled respectively to two primary coils 30 and 31, the former beingincluded in a closed oscillatory circuit 32 tuned to a frequency of, forexample, 50,000 cycles: per second and the latter being included in aclosed, oscillatory circuit 33 tuned to a frequency of, for example,35,000 cycles per second. Variable condensers 34 and 35 are respecandthe tuning of the ci quency above audibility tively included in thecircuits 32 and 33,

rcuits is adj usted according as'the system is used for telephony ortelegraphy. If the former a freis employed, and

if the latter afrequency within audibility is employed.

Oscillations of the desired secondary frequency of, for example, secondare pr'oduced in th autodyne or thermionic ranged to be controlled bycuit 37 and controlling a 50,000 cycles per e circuit 32 by anoscillator 36 ar an oscillatory circircuit 38 including the oscillatorycircuit 32. The circuit 38 also includes'a battery 40, or other sourceof current, a control key 41, and a ticklercoil.

42 arranged in operative relation to a coil 43 in the oscillatorycircuit 37. The circuit 37 also includes a secondary coil 44 and avariable condenser to control the oscillator 3 manner,

45, all connected 6 i a Wel known Oscillations of the desired secondaryfre quency of, for example, 35,000 cycles per second are produced in thecircuit 33 by an autodyne or thern'iionic oscillator e6 arranged to becontrolled by an oscillatory circuit 47 and controlling a circuit 43including the oscillatory circuit The circuit 43 also includes a battery50, or other source of unidirectional current, a. control key 51, and atickler coil 52 arranged in operative relation to acoil 53 in theoscillatory circuit 4:7. The circuit 4-7 also includes a secomlary coil54: and a variable condo 315 all connected to control the os-iillato. ina well known manner.

For impressing upon. the periodically modified radiant waves emitted bythe as rial circuit amplitude variations corresponding to sound waves toform a telephonic message, a telephone transmitter is arranged in acircuit 61 including a battery 62 and a key 63, the last named servingto maintain the circuit 61 open when signals or messages are not to betransmitted. This circuit 61 also includes two primary coils 6-1; and 65which are inductively coupled respectively to the secondary coils 414iand 54; of the circuits 3'? and 4:7.

When the above described transmitting system is employed solely fortelegraphic coinmunication, either wireless or by wire, the circuit 61is omitted, and the tuning of the circuits 37 aud t? is such as toproduce heats within audibility, Thus the circuit 37 may be tuned to afrequency of 30,000 cycles per second and the circuit 47 tuned to a hequen y of 29,000 cycles per second, thereby giving a beat frequency of1,000 cycles per second which is within audibility. A telegraphicmessage may be sent by use of any one of the keys 18, 41 or 51.

For receiving the waves or impulses emitted from the transmitting systemof Fig. 1, one form of receivin system is shown in Fig. 2, comprising anopen, aerial circuit hav ing a primary inductance 71 and grounded at 72.This aerial circuit 70, 71 and 72 is inductively coupled through itsprimary coil 71 with a closed, oscillatory circuit 7 3 including asecondary coil 7 1 and a variable condenser 75. This circuit 73 is tunedto the natural period of vibration of the aerial cir cuit T0, 71 and752, here 1,000,000 cycles per second, and is arranged to controlthermionic valve or detector 80.

The detector is arranged to Control a circuit 81 including a battery 82,two primary coils 33 and 81 and a tickler coil 35, the latter beinglocated with respect to the secondary coil 741 to give the desiredsensitiveness. The primary coils 83 and 8 1 are included in a closed,oscillatory circuit 86 having a variable condenser 37 and being tuned tothe aforesaid frequency of 1,000,000 cycles per second For the purposeof selecting the desired secondary frequencies, the circuit 86 isinductively coupled through its primary coils S3 and 8a to twooscillatory circuits 90 and 91, the one including a secondary coil 92and a variable condenser 93, and the other including a secondary coil 94and a variable condenser The oscillatory circuit 90 is tuned to thefrequency of one of the incoming secondary frequencies, for example,50,000 cycles per second, and is arranged to control a thermionic valveor detector which controls a circuit including a battery 101, a primarycoil 102 and a tickler coil 103. The primary coil 102 is included in anoscillatory circuit .104- ha ing a variable condenser 105 and beingtuned to the secondary frequency of 50,000 cycles per second. Theoscillatory circuit 91 is tuned to the other incoming secondaryfrequency of 35,000 cycles per second, and is arranged to control athermionic valve or detector 110, which in turn controls a circuitincluding a battery 111, a primary coil 112 and a ticlrler coil 113. Theprimary coil 112 is included in an oscillatory circuit 114 having avariable condenser 115 and being tuned to the secondary frequency of35,- 000 cycles per second.

For causing the two series of selected pcriodic variations to producebeats, the two oscillatory circuits 1041 and 11 1 are inductivelycoupled to a common untuned circuit 116 including two secondary coils117 and 118 arranged in operative relation respectively to the twoprimary coils 102 and 112. This circuit 116 is arranged to control a.thermionic amplifier or detector 120, the out put circuit 121 of whichincludes a battery .122, a primary coil 123 and a tickler coil 12 1-.The coil 12% is coupled to a coil 125 in the circuit 116 in a manner togive the desired sensitive action. The primary coil 123 is included inan oscillatory circuit 126 tuned to the beat frequency of 15,000 persecond for telephony and 1,000 cycles per second for telegraphy andincluding a variable condenser 1.2T.

For amplifying the beat frequency of the circuit 126 the primary coil123 is inductively coupled to a secondary coil 130 in a circuit 131which also includes an oscillatory circuit 132 having a variablecondenser 133. The circuit 131 is arranged to control an amplifier ordetector 134 which in turn controls a receiving circuit 135 comprising abattery 136, a suitable receiving instrument 137 and a tickler coil 133,the latter being suitably located with respect to the oscillatingcircuit 132 to give the required sensitive action.

In the foregoing the thermionic valves and oscillators 80, 100, 110, 120and 134- have been identified generally and may be of any suitable type,but as here shown each, prefstably, consists of an evacuated glass bulb141, a grid 1412 and a filament 143, this latter element being containedin and heated by a local circuit. 1445 having; a battery 1&5 andadjustable resistance 146. In Fig.3 the controlled. circuit 121 includesthe receiving instrument B37, and the connected amplifying-circuits aredispensed with. This rangement is employed where amplification of thereceived signals is unnecessary 7 Having: thus fully described thisinvention, I claim:

1. A method of transmitting and receiving. energy which consists ingenerating a series of: impulses having inqpressed therein apluiuilityof series of modifications of different frequencies respectively,receiving some of the energy of said impulses and modifications andcausing the same tocoopcrate in producing a wave having a fre quencydetermined solely by said first-mentioned frequencies.

A method of transmitting and receiving energy which consists ingenerating a series at impulses having impressed therein a plurality ofseries of periodic modifications of dilferent frequencies respectively,receiving some of the energy of said impulses and modifications andcausing. the s (e to cooperate in'produeiirg: a: tone: hav- 11- g: a;frequency within the limits of audibility and controlled solely by thefrequencies of said modifications.

3. A method of transmitting and receiving energy which consists ingenerating a series of impulses havinga frequency'above andibility andhaving impressed therein twoseries of periodic variation havingfrequenciesabove audib 1 y and diilering irom each other by a clearlyaudible" equ-ency, rcce T- ing' some of the energy of said impulses andproducing as a result of theaction? of said variatitms a current havinga frequency equal to the difference between the frequencies of saidvariations.

l. A method of signaling which consists in generating a series of wavesmodulated simultaneously by a plurality of series of variations havingdifferent frequencies respectively, receiving some of the energy of saidwaves and variations, producing therefrom a plurality of series ofoscillations having frequencies cmampondiug to said firstmentionedfrequencies respectively, and causing said oscillations to cooperatesimultaneously in producing a current modified at a frequency determinedsolely by said firstmentioned frequencies.

A. method of signaling which consists in transmitting a series of wavesmodulated simultaneously by two series of variations havingdifferentfrequencies respectively, re ceiving some of the energy of saidwaves, producing therefrom two series of oscillations having frequenciescorresponding to said fnst-m'entionedv frequencies r especti vel y, andcausing said. twoseries of oscillations t'o' cooper-arts simultaneouslyin producing a tone? having a frequency conti said firstunenitionedlireqiucuciesa y 6'. A method of signalling" which consists iiitransmitting waves varied by two series of mod::lati'ous havingdifferent frequer -'cs respectively and differing in frequency by afrequency within; thelimi'ts of aud i'bility, receiving some of theenergy of said waves and producing tl rerefrom; electric beats having' afrequency corresponding to the dilference between said first-mentionedfrequencies;

7. A method of signalling which consists in transmitting a series ofwaves havin a frequency outside of the a e of audibility andhavingsimultaneously nn ed there two series of modulations of differentfre quencies respectively, receiving said waves and modulations, produc1 g therefrom impulses caused by the simin aneous action of saidmodulations andv having a frequency equal to the dillcrence between thefrequencies ofsaid modulations, and varying one of said series ofmodulations to form signals.

8.- A; method of. signaling which consists in. transmitting a series ofwaves having a frequency outside of the range of .audibil'ity and havingsimultaneously impressed therein two series of modulations of differentfrequencies:-1'espectively, the dilference between said diiferenltfrequencies being a frequency within the range of aridibil'ity,receiving said waves and modulations, producing therefrom'imprilsescaused by the simultaneous action of said modulations and havingfrequency equal to the difference bctween 'he frequencies of saidmodulations, and varying one-of said series of modulations: to formsignals;

9. A method of" signaling which consists in transmiting a series ofwaves having impressed therein a plurality of series of periodicvariations having different frequencies respectively, receiving some ofthe energy of said waves and variations, causing the same to produce awave having a frequency determined solely by said variations andmodifying one only of said plurality of series of variations to producesignals.

10. In a system for receiving a series of waves having impressed thereintwo series of periodic variations dill'ering in frequency one from theother by a clearly audible frequency, a circuit responsive to the seriesof waves, two circuits controlled by said firstmentioned circuit andtuned to respond respectively to said two series of variations, acircuit controlled by the joint action of said two circuits and adetector controlled by "said last mentioned circuit.

11. In a system of signaling, the combination wlth means for generatinga series of 'so'lely by llo said detector and tuned to said clearly aucible frequency.

12. In a system of signaling the combination with means for generating aseries of waves having impressed therein two series of periodicvariations differing in frequency by a clearly audible frequency, ofmeans for receiving said waves and variations including a circuitresponsive thereto, a detector controlled bysaid circuit, two circuitstuned to respond selectivelyto said two series of periodic varictionsrespectively two thermionic valves controlled by said two circuitsrespectively, a circuit controlled by the joint action of said valves,and a detector controlled by said last mentioned circuit.

18. In a system of signaling, the combination with means for generatinga series of waves having impressed therein two series of periodicvariations differing in frequency by a clearly audible frequency, ofmeans for receiving said waves and variations including a circuitresponsive thereto, a detector controlled by said circuit, two circuitstuned to respond selectively to said two series of periodic variationsrespectively, two thermionic valves controlled by said two circuitsrespectively, a circuit controlled by the joint action of said valves, adetector controlled by said last mentioned circuit, an amplifiercontrolled by said last mentioned detector and an indicator controlledby said ampli fier.

14. A receiving system for signaling, comprising a receiving circuit, adetector controlled by said circuit, two circuits controlled by saiddetector and tuned respectively to two frequencies differing by aclearly audible frequency, two thermionic valves controlled by said twocircuits respectively, a circuit controlled jointly by said valves, andan indicator controlled by said last-mentioned circuit.

15. A. receiving system for signaling comprising a receiving circuit,adetector controlled by said circuit, two circuits controlled by saiddetector and tuned respectively to two frequencies differing by aclearly audible frequency, two thermionic valves controlled bysaid twocircuits respectively, a circuit controlled jointly by said valves, adetector controlled by said lastmentioned circuit, an amplifiercontrolled by said last-mentioned detector and a receiving devicecontrolled by said amplifier.

16. A receiving system for signaling, comprising a receiving circuit, adetector controlled by said circuit, two, closed, oscillatory circuitstuned to two frequencies re spectively, said frequencies differing by aclearly audible frequency, two amplifiers controlled by said two,closed, oscillatory circuits respectively, two, closed, oscillatorycircuits controlled by said amplifiers respectively, an untuned circuitcontrolled by said last-mentioned, two circuits, a detector controlledby said untuned circuit, a circuit controlled by said last-mentioneddetector and tuned to said clearly audible frequency, and a receivingdevice controlled by said lastmentioned circuit.

This application signed this 6th day of July, 1923.

JOHN HAYS HAMMOND, JR.

